That looks a lot like the pesenti made max van tuyls (had one a while ago). I wouldn't be surprised if they produced them for bianchi.
Why would they be? Bianchi were perfectly able to produce those themselves.
I'm not saying they didn't produce it but apart from the internal rear mech cable routing, it looks exactly like the pesenti built van tuyl maxes (all fillet brazed except for the single lugged joint of the seattube).
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@Carabo started
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That looks a lot like the pesenti made max van tuyls (had one a while ago). I wouldn't be surprised if they produced them for bianchi.